1. Technical Field
The present invention relates to plating methods and electronic devices.
2. Related Art
A subtractive method and an additive method are known as a method for forming wiring patterns. In the subtractive method, a metal layer is formed over the entire surface of a substrate, a photoresist is formed on the metal layer by patterning, and the metal layer is etched by using the photoresist as a mask. In the additive method, a photoresist is formed on a substrate by patterning, and a metal layer is deposited by a plating process in an opening section in the photoresist. These methods may entail problems concerning consumptions of resources and raw material, in view of the fact that the photoresist is finally removed, and further in view of the fact that a part of the metal layer is removed in the subtractive method. Also, they require the steps of forming and removing a photoresist, which results in a large number of manufacturing steps. Furthermore, the solvent that is used to remove the photoresist may possibly remove, for example, the catalyst, too. An example of related art is described in Japanese laid-open patent application JP-A-8-64934.
In accordance with an advantage of some aspects of the present invention, a plating method that can improve the reliability of devices with a relatively simple process, and devices manufactured by the plating method can be provided.
(1) A plating method in accordance with an embodiment of the invention includes the steps of: (a) forming a roughened area in a predetermined area of a substrate; (b) forming a surface-active agent layer above at least the roughened area; (c) forming, above the roughened area, a catalyst layer above the surface-active agent layer; and (d) precipitating a metal layer above the catalyst layer.
According to the embodiment of the invention, because the metal layer is formed above the roughened area of the substrate, adhesion between the substrate and the metal layer can be improved and the reliability can be improved. Also, surfaces of the substrate other than the area of the metal layer are not roughened, such that the strength of the substrate is not impaired, and therefore the area that is not roughened can be used for a wide variety of purposes. Moreover, for example, the use of photoresist can be omitted, such that a metal layer can be formed with a relatively simple process. It is noted that, in the invention, the case where B is provided above a specific A includes the case where B is provided directly on A, and the case where B is provided above A through another member. The same applies to other embodiments of the invention to be described below.
(2) In the plating method, the step (a) may include forming another surface-active agent layer other than the predetermined area of the substrate, and etching the substrate by wet-etching to thereby form the roughened area.
(3) In the plating method, the substrate may exhibit a first polarity, and the surface-active agent layer and the other surface-active agent layer may exhibit a second polarity.
(4) The plating method may further include removing the other surface-active agent layer before the step (b), and patterning the surface-active agent layer to be remained only above the roughened area in the step (b).
(5) In the plating method, the step (b) may include patterning the surface-active agent layer by light irradiation in a manner that the surface-active agent layer remains only above the roughened area, and removing the other surface-active agent layer by the light irradiation.
(6) In the plating method, the substrate and the other surface-active agent layer may exhibit a first polarity, and the surface-active agent layer may exhibit a second polarity.
(7) In the plating method, an absolute value of the first polarity of the other surface-active agent layer may be greater than that of the substrate.
(8) In the plating method, in the step (b), the surface-active agent layer may be formed above the roughened area and above the other surface-active agent layer.
An electronic device in accordance with an embodiment of the invention includes a wiring pattern, wherein the wiring pattern is formed by the plating method described above.